- Researchers found a groundbreaking technique to alter the electronic structure of a copper atom.
- They made copper catalysts exhibit noble metal-like chemical characteristics.
- The new material cannot replace an original gold element, but it can substantially reduce the use of rare, expensive materials in factories.
With the increasing environmental and energy problems, it has become necessary to develop clean coal technologies to synthesize high value-added chemicals. The most popular industrial application is the synthesis of alcohols from coal through syngas (carbon monoxide and hydrogen).
In recent years, copper-based catalysts have been extensively studied, and scientists have been able to achieve very high yields of ethylene glycol and rational insights that could be extremely useful in the synthesis of fine chemicals and pharmaceutical products.
Now, a team of researchers at the Chinese Academy of Sciences have altered the chemical properties of copper catalyst that affect its electronic structure. They have modified catalyst’s properties in a way that it behaves more like silver or gold.
How Did They Do It?
Researchers used external energy to alter the electronic structure of a copper atom, forcing the element to exhibit noble metal-like chemical characteristics. Usually, these chemical characteristics depend on the electronic structure of the atoms in the catalyst.
For years, scientists have been studying silica-supported copper catalysts, which easily get oxidized and form copper ions, instead of gold or silver. The process involves dissolving copper salts in a mixture of ammonia and water to coat copper onto silica particles, which is then heated to vaporize the ammonia gas.
Hexagonal rotating chamber | Courtesy of researchers
In this study, researchers used a gas-phase sputtering methodology: they used high-energy argon plasma to eject each copper atom from a pure metal sheet. Ejected atoms are then evenly coated onto silica particles inside a customized hexagonal rotating chamber.
Reference: Science Advances | doi:10.1126/sciadv.aau3275 | CAS
The team analyzed the catalysts produced in this method using various X-ray spectroscopy techniques and they found that catalysts are copper phyllosilicates. These nanoparticles are very difficult to oxidize and have catalytic performance similar to that of silver or gold.
Is Copper the New Gold?
Although the resulting material exhibits catalytic performance very similar to that of gold, it can’t be used to make fake gold pennies because its density remains the same as original copper.
Many electronic devices contain a large amount of platinum, silver, and gold. Smartphones, for instance, can have as much gold as a ton of ore. Since copper contain fewer electrons (29) than gold (79), it cannot replace gold in industrial applications as well.
The researchers described their material as being ‘like a warrior with golden armor’, resisting the chemical erosion even at high temperatures. | Credit: Chinese Academy of Sciences
Copper electrons are also relatively unstable, thus they react more easily with other substances. What researchers have done in this study is monumental and impressive: they injected a massive amount of energy into copper atoms and made electrons more stable and dense.
The resulting material can withstand erosion and high temperatures. It will substantially reduce the use of rare, expensive materials in factories.